Radial and thrust bearing

ABSTRACT

A bearing is disclosed comprising a rotatable shaft and a coaxial unitary member. The shaft is shaped to provide a ball inner race and at least one roller inner race. The coaxial member has an inside annular protrusion extending toward the shaft. The protrusion has a curved shoulder on one side and a straight shoulder on the other side. The curved shoulder will support a high axial thrust along one direction of the shaft; the straight shoulder will support a relatively low axial thrust applied along the shaft in the opposite direction. The outer unitary member is made by cold-forming a low carbonsteel tube with a die, carburizing, and then heating the thusformed outer race in an inert atmosphere, sizing, and which after quenching, provides a hard outer race. The shaft is made by rolling the ball inner race and at least one roller race into a rod which has been carburized and then heated in an inert atmosphere.

United States Patent Elmore et al.

[4 1 Aug. 12, 1975 Primary ExaminerM. Henson Wood, Jr. AssistantExaminerRichard A. Bertsch Attorney, Agent, or FirmFrank S. TroidlABSTRACT A bearing is disclosed comprising a rotatable shaft and acoaxial unitary member. The shaft is shaped to provide a ball inner raceand at least one roller inner race. The coaxial member has an insideannular protrusion extending toward the shaft. The protrusion has acurved shoulder on one side and a straight shoulder on the other side.The curved shoulder will support a high axial thrust along one directionof the shaft; the straight shoulder will support a relatively low axialthrust applied along the shaft in the opposite direc- The outer unitarymember is made by cold-forming a low carbon-steel tube with a die,carburizing, and then heating the thus-formed outer race in an inert andwhich after quenching,

The shaft is made by rolling the ball inner race and at least one rollerrace into a rod which has been carburized and then heated in an inertatmosphere.

7 Claims, 11 Drawing Figures 1 RADIAL AND THRUST BEARING [75] Inventors:J. Russell Elmore, New Hartford;

Carl F. Benson, Torrington, both of Conn. [73] Assignee: The TorringtonCompany,

Torrington, Conn.

[22] Filed: Nov. 29, 1973 [21] Appl. No.: 420,013

Related U.S. Application Data [62] Division of Ser. No. 311,302, Dec. 1,1972, Pat. No.

[52] US. Cl. 308/174 [51] Int. Cl. Fl6c 19/04 tion. [58] Field of Search308/174, 175; 29/1484 R, 29/1484 A [56] References Cited atmosphere,Sizing UNITED STATES PA S provides a hard outer race.

3,131,006 4/1964 Anderson 308/174 3,424,507 l/l969 Rollins et al 308/1743,532,400 10/1970 Benson et al. 308/174 3,610,714 10/1971 De Gaeta308/174 l r U PATENTED AUG 1 2 [975 SHEET "1 30 2a 32 3e 26 LPATENTEDAUGIZIBYS 3.899225 SHEET 2 7 A as FIG. /0

v FIG/l I06 I00 I08 96 RADIAL AND THRUST BEARING This is a division ofapplication Ser. No. 31 1,302 filed Dec. 1, I972, now US. Pat. No.3,795,960 dated Mar. 12, 1974.

This invention relates to radial and thrust bearings. More particularly,this invention is a new and improved radial and thrust bearing, and anew and improved method for making the inner race and the outer race ofsaid bearing.

For certain uses, a bearing must be capable of taking a high radialload, a high thrust load in one direction, and a light thrust load inthe opposite direction. One example is an automobile water-pump bearing.

My new radial and thrust bearing is a highly efficient compact radialand thrust bearing consisting of only a few parts. The bearing handles ahigh radial load, a high axial thrust load in one direction, and a lightthrust load in the opposite direction.

Briefly described, the bearing includes a rotatable shaft shaped toprovide a ball inner race and at least one roller inner race. The outerbearing comprises a coaxial unitary member. An annular protrusion isprovided in the unitary member. The annular protrusion extends towardthe shaft and has a curved shoulder on one axial side and asubstantially straight shoulder on the other axial side. A ring of ballsis adapted to rotate on the inner and outer ball races. A ring ofrollers is adapted to rotate on the inner and outer roller race orraces. The curved shoulder on the annular protrusion will support thehigh thrust through the ring of balls; the straight shoulder willsupport the relatively light thrust through the rollers, and both theballs and the rollers will support the radial and couple loads.

Currently, high carbon-content steel rods and tubes are used to makeradial and thrust bearings. High carboncontent steel must be machinedand ground to form the races which requires complicated grindingmachines. The machining and grinding operations weaken the shaft and/orouter race.

With our new method, both the outer unitary member and the rotatableshaft are made from a low carbon-content steel. Low carbon-content steelcan be cold-formed, thus eliminating the grinding steps formerlyrequired. The cold-formed shaft and outer race are carburized, heated,and then quenched to form hard steel members. This results in not only acheaper bearing, but a bearing consisting of steel parts which aretougher than the steel parts in formerly-made bearings.

The invention, as well as its many advantages, may be further understoodby reference to the following detailed description and drawings, inwhich:

FIG. 1 is an elevational view, partly in section, showing onemodification of the invention;

FIG. 2 is a front view of the thrust-ring spacer of FIG.

FIG. 3 is an elevational view, partly in section of an othermodification of the invention;

FIG. 4 is a side elevational view, partly in section, of a furthermodification of the invention;

FIG. 5 is an elevational view, partly in section, of a still furthermodification of the invention;

FIG. 6 and FIG. 7 are sectional elevational views, useful in explainingour new method of cold'forming the outer unitary member;

FIGS. 8 and 9 are elevational views useful in explaining our new methodof forming the ball race and roller races on the rotatable shaft, and

FIG. 10 and FIG. 11 illustrate an alternative method of forming the ballrace and roller races on the shaft.

Like parts in all the figures are referred to by like numbers.

Referring to FIG. 1, the rotatable shaft 10 may be a water-pump shaft.When used in a water pump, the end 12 is connected to the pump impeller,and the end 14 is connected to the fan.

The rotatable shaft 10 includes an integral substantially semicircularannular ball race 16. The adjacent cylindrical surface of the shaft 10is used as a roller inner race. Balls 18, arranged in the ball cage 20,roll along ball inner race 16; rollers 22, mounted in the roller cage24, roll around the outside of the shaft 10.

The coaxial unitary outer member 26 includes an integral annularprotrusion 28, extending toward the shaft 10. The annular protrusion isshaped to provide a curved shoulder 30 on one axial side and asubstantially straight shoulder 32 on the other axial side. The curvedshoulder will support the high thrust from the pump impeller and fanthrough shaft 10 and through the balls 18. A portion of the insideperimeter of the unitary member 26 provides the outer roller race.

A thrust collar 34 is fixedly mounted about the shaft 10 adjacent theaxial outer ends of the rollers 22. The thrust collar axially locatesthe rollers and cage 24 in the outer unitary member 26, and transmitslight thrust of the shaft, to the roller ends.

A thrust-ring spacer 36 is mounted within the unitary member 26. Thethrust ring spacer has one edge in contact with the straight shoulder 32on protrusion 28, and the other edge in contact with the axial inneredges of the rollers 22. Thus, any small thrusts, such as caused byvibrations in the fan connected to shaft 10, is transmitted through thisshaft collar, the rollers, the thrust-ring spacer, and against thestraight shoulder. Movement of the cage axially is prevented by theprotrusions 38 extending inwardly from the thrust-ring spacer, as shownin FIG. 1 and FIG. 2.

In the embodiment of FIG. 3, the rollers 22 bear directly against theshoulder 32, making a thrust-ring spacer unnecessary. Also, a second setof rollers 40 is located on the other side of the ball race 16 from thelocation of the first set of rollers 22. Rollers 40 and cage 42 areprevented from falling out of member 26 by a fixedly-mounted thrustcollar 44.

In the embodiments of FIGS. 1, 3, and 5, the minor diameter of the ballrace 16 on the shaft is approximately the same as the shaft diameter.However, in the embodiment of FIG. 4, a ball inner race 46 is providedin the shaft 10 with a minor diameter less than the shaft diameter. Theshafts of the embodiments of FIGS. 1, 3, and 5 are much stronger andmore fatique-resistant than the shaft shown in the embodiment of FIG. 4.However, the embodiment of FIG. 4 is satisfactory for certain operationswhich do not require an extremely strong shaft.

In the embodiment of FIG. 5, the thrust-ring spacer 50 has noprojections. The ring spacer has one edge bearing against shoulder 32,and the other edge bearing against rollers 22. The projections areunnecessary because the roller cage 52 is located against axial movementby the shoulder 54 on the outer edge of the ball inner race 16.

In practicing my new method for making an outer race for a radial andthrust bearing, the tubular sleeve 60, shown in FIG. 6, may be made of alow carboncontent steel and may be formed from an extruded tube, weldedtubing, or flat strip stock.

An important step in the method is the formation of the annularprotrusion 28 by a cold-forming method. As shown in FIG. 7, theprotrusion 28 is formed in a die, including punches 62 and 64. Punch 62includes a curved end 66, and annular shoulder 67, which press againstthe tube 60 to form the curved shoulder 30. Punch 64 has a flatcylindrical end 68 and annular shoulder 69, which press against the tube60 to form the substantially straight shoulder 32 and the roller outerrace. Thus, the punches are shaped to provide the ball outer race andthe roller outer raceway in the interior of the unitary member.

The cold-formed unitary outer race is then removed from the die,carburized, and then heated into the austenitic range in a furnace, orby induction heating, to a temperature of at least 1400 degrees F. Theheating is done in an inert atmosphere such as nitrogen, or in acarburizing atmosphere. The outer race 60 is then quenched and sized.This can be done: (I) by pushing a properly-formed plug into each end ofthe race and pushing the entire assembly into quenching oil, or (2)dropping the race between rollers to roll the outside diameter to propersize and straightness, and then flooding it with quenching oil toharden. The sizing operation is carried out in an inert atmosphere, suchas nitrogen.

As shown in FIG. 8, a low-carbon-content steel rod 70 may be used tomake either a shaft having a ball race with a minor diameter less thanthe shaft diameter, or with a minor diameter equal to the shaftdiameter. The low-carbon-content rod is carburized and then heated in aninert gas or carburizing atmosphere to the austenitic range of l400F orabove in a furnace or by induction heating. The heated rod is thenplaced in a rolling machine which includes the rollers 72 and 74 of FIG.9. The rollers include annular grooves 80 and 82 adjacent protrusion 76,and annular grooves 84 and 86 adjacent protrusion 78. The rollers rollthe ball race 46 of the modification shown in FIG. 4 in an inertatmosphere. This ball race has a minor diameter less than the shaftdiameter. The rollers also roll the roller inner races and straightenthe shaft at the same time. The thus-formed inner race is thenflooded'with quenching oil to harden.

In order to form the inner race of FIGS. 1, 3 and 5, the shaft 70, oflow carbon content, is bulged at the desired axial position by acold-forming die before it is carburized. As shown in FIG. 10, the shaftis bulged at 88 by two dies 90 and 92. The bulged shaft is carburized,heated into the austenitic range in an inert or carburizing atmosphere,and then placed into the rollers 94 and 96 of FIG. 11. The rollers 94and 96 are provided with annular protrusions 98 and 100, respectively,and annular grooves 102 and 104 on the roller 94, and annular grooves106 and 108 on roller 96. The inner ball race 16 is formed on the shaft10, as well as the adjacent inner roller race or races in an inertatmosphere. The shaft is simultaneously straightened by the roller-racerollers. The rolled shaft is then quenched with quenching oil to hardenthe shaft.

We claim:

1. In combination: a rotatable shaft shaped to provide a ball inner raceand at least one roller inner race adjacent the ball race; a coaxialunitary member having an annular protrusion extending toward the shaft,said annular protrusion having a curved shoulder on one axial side and asubstantially straight shoulder on its other axial side, the curvedshoulder providing the ball outer race, and at least a portion of theinside perimeter of the unitary member providing the roller outer race;balls positioned in the ball races; rollers positioned in the rollerraces; and a thrust collar fixedly mounted about the shaft adjacent theaxial outer ends of the rollers, and thrust transmitting means includingat least the thrust collar and further including a member bearingdirectly against the substantially straight shoulder for transmittingthrust from the shaft and against the substantially straight shoulder.

2. The combination of claim 1 wherein the rollers bear directly againstthe substantially straight shoulder.

3. The combination of claim 1 wherein: a thrust ring spacer is mountedwithin the unitary member with one edge in contact with thesubstantially straight shoulder and the other edge in contact with theaxial inner ends of the rollers.

4. The combination of claim 3 wherein: a cage separates the rollers, andthe thrust ring spacer has a plural ity of projections which limit theaxial movement of the cage.

5. The combination of claim 1 wherein: the shaft is shaped to provide aninner roller race adjacent each side of the ball race, there are twosets of rollers with one set located adjacent each side of the ball raceand a second thrust collar is fixedly mounted about the shaft to limitthe axial movement of the second set of rollers.

6. The combination of claim 1 wherein: the minor diameter of the ballrace on the shaft is approximately the same as the shaft diameter.

7. The combination of claim 1 wherein: the minor diameter of the ballrace on the shaft is less than the shaft diameter.

1. In combination: a rotatable shaft shaped to provide a ball inner raceand at least one roller inner race adjacent the ball race; a coaxialunitary member having an annular protrusion extending toward the shaft,said annular protrusion having a curved shoulder on one axial side and asubstantially straight shoulder on its oTher axial side, the curvedshoulder providing the ball outer race, and at least a portion of theinside perimeter of the unitary member providing the roller outer race;balls positioned in the ball races; rollers positioned in the rollerraces; and a thrust collar fixedly mounted about the shaft adjacent theaxial outer ends of the rollers, and thrust transmitting means includingat least the thrust collar and further including a member bearingdirectly against the substantially straight shoulder for transmittingthrust from the shaft and against the substantially straight shoulder.2. The combination of claim 1 wherein the rollers bear directly againstthe substantially straight shoulder.
 3. The combination of claim 1wherein: a thrust ring spacer is mounted within the unitary member withone edge in contact with the substantially straight shoulder and theother edge in contact with the axial inner ends of the rollers.
 4. Thecombination of claim 3 wherein: a cage separates the rollers, and thethrust ring spacer has a plurality of projections which limit the axialmovement of the cage.
 5. The combination of claim 1 wherein: the shaftis shaped to provide an inner roller race adjacent each side of the ballrace, there are two sets of rollers with one set located adjacent eachside of the ball race and a second thrust collar is fixedly mountedabout the shaft to limit the axial movement of the second set ofrollers.
 6. The combination of claim 1 wherein: the minor diameter ofthe ball race on the shaft is approximately the same as the shaftdiameter.
 7. The combination of claim 1 wherein: the minor diameter ofthe ball race on the shaft is less than the shaft diameter.